Organic material



Aug. 7, 1945."

' METHOD OF REMOVING VOLATILE ORGANIC MATERIAL Filed March 13, 1942 T STEAM AND IVAPHTHA VAPOR AQUEOUS IVA/ H 7H4 6 ON TA/N/NG flfTERGE/VT STEAM AQUEOU$ DETERGENT INVENTOR w. A. FESSLER 2,381,658

Will/AM A. FfSSLER PatentedAug. 7, 1945 ivm riron' 0F REMovINo-vomrnn ORGANIC MATERIAL, I

amillusQN. Y., assignor to The Solvay Process Gompan New York,

,This invention; relatesto detergent-composh tions and is particularly,concerned with the puri-. fication of aqueous solutions ofldetergents of good foamingquali-ties. a l a. t

ousv detergent; solutions it I frequently happens that substantialiquantitieszof volatile organic ma-;

terialare; introduced into the solutions; .Thus, in the purif cation: of; detergents derived from hy-t drocarbon.; s9urces it is often desirable to remove unconverted water insoluble materials by exm a acture ormanipulation new;

, l i eorporation of New York Application lvl arch 13, 1942, Serial No. 434,578

' rec ai s. (01.20246) from such detergents in this manner involves a relativelyhigh capital cost for equipment;

"The'present invention has for its Objectinfi-fl movements in the removal of volatile liquid hydroc'arbon constituents from aqueous detergent I solutions and is particularly concerned with a traction with .9, Y volatile liquid hydrocarbon such as, a petroleum naphthaau-Aqueous detergent S0--.- lutionsare capableof; holding1:on the order of:

6% to1Q%;;or moreof Suchwolatile-Jliquid hydrocarbons in a statego-i pseudo or colloidalsolu tion. t t

sirable to'recover theiivolatileliquid hydrocani bons. Further, their separation from the'aquecusideterl'geiit solutions is alsodesirahlefor other,

reasons Th esence iY9 i1Bi d d carbons in ,adueous "solutions of ,the I detergents is objectionable because jof their adverse effect u t dete wa -ran nd W t ng; ability of the solutions, and because of lthefire hazard associated, with their infiammabilityv When present in aqueoussolutions of detergents which are t 'o 'be'fconvertgedito thesolid viorm, they on ti ut aijfi a dre bl fi haza ample; they form explosive mixtures when, the solutions are spray-dried inhot air or when'the solutions are .druin driedflin fcon'tact with air. Herlcefit isfdesirab lefprior to thelfinal drying operation, to reduceth'e amount of such hydrocarbons c'ontained f'n' aqueous c'letergent solu tions'of the type under) consideration to (1.5%. or lessbyuieightg If the} volatile; liquid hydrocarbons, are're movedfro'm' aqueous "detergent solutions J by batchwise distillation; "the process at first pro For eco ion ical operation itis usually de-H distillation process which minimizes foam for mation and thereby reduces the cost of-flequipment necessary for distilling the hydrocarbons from the detergent solution;

"The process ofthe present invention-is -particularly applicable to the treatment .of aqueous detergentsolutions of the type produced by the process-of 'myapplication Serial No; 427,32}; filed January 19,1942; In accordance 'with'theprocess ofthat applicationorga'nic nitrosatiori ceeds satisfactorily." After'thehydrocarbons are partially depl eted,-*hovveve'r; the "quantity i of foam increases and by its abundance hinders further conduct of the process'whi'ch must then be completed: slowly and carefully to avoid "carrying foam along-"with vapor and causing a loss of detergent in the distillate. Since the distillation must be' eflfected slowly, the distillation capacity of apparatus of given size-is relatively-low com pared with. its capacity for"ordinary distillationsi Consequently the removal of- 1 the liydrocarbo'ns' sulfitation products, such as the products" of United States Patent 2,265,993, are subjected to an extraction with a volatile liquid hydrocarbon such ashexane, heptane, octane,-he'xene,'heptene, octene, or mixtures of such hydrocarbons, in the presence of an emulsion breaker suchas isoprop-yl alcohol. The aqueous detergentsot the type thus extracted produce an abundance i of 'foam and therefore present. an-especially difficultlconcentration problem. l to -In the ordinary distillation method, the hydrocarbons maybedistilled satisfactorily along-with watertuntil the concentration of; ,thehydrocarv bons has been reduced tea-point somewhat; be-' low 5%, since the. foaming tendency .isnot so. noticeable at higher concentrations (referred to herein as foam-breaking concentrations); but;

about at this pointin the process the teaming increases rapidly until it becomes exceedingly diflicultto continue the distillation without in;

curring substantial losses of aqueous detergent solution along with Water jandhydrocarbori vapor. .The concentration of the hydrocarbons in the solution 'at the aforesaid point in the process is referred to here n as the minimum loam breaking concentration,

'Theprocessof my invention provide a simple and effective solution of this difficulty;

' In accordance with the processor the present invention, an aqueous solution of .a detergent ofgood foaming qualities containing one or more volatile liquid hydrocarbons (that is, liquid'hy'-- drocarb'ons having normal boiling points below C.) mo'r'e particularly non-aromatic hydro'- carbons (ii e., open-cha n aliphatic and alicyclic hydrocarbons) having normal boiling points in-* or more, the head of foam the range 50 to 150 C. is passed down through an evaporating column countercurrently to a flow of a hot inert gaseous evaporating medium such as steam, and at least a sufficient concentration of the said liquid hydrocarbon or hydrocarbons (i. e. at least the minimum foam-breaking concentration) is maintained, in liquid form, at the top of the liquid phase in the column (i. e. at the top of the countercurrent flow in the column) to substantially reduce the head of foam on the aqueous detergent.

In the practice of the present invention in accordance with a preferred method of procedure, the aqueous detergent solution containing .one or more liquid hydrocarbons having normal boiling points between 50 and 150 a hydrocarbon stripping zone at or near the top thereof, and an aqueous detergent solution from which the liquid hydrocarbon has been removed is withdrawn from a point near the bottom of this zone; steam is passed upwardly through the zone to evaporate the liquid hydrocarbon from the aqueous solution; and a high concentration of the liquid hydrocarbon, at least 5% .by weight, is maintained at the upper surface of the .zone to accelerate the breaking of foam. By maintaining theconcentration of said liquid hydrocarbon in the aqueous detergent solution at the upper surface of the solution in the evaporating zone at 5 present may be dwarfed to a fifth or a tenth of the height which it may attain in the absence of this quantity of liquid hydrocarbon and a detergent solution may be produced containing less than 0.3% of hydrocarbon. The high concentration of liquid hydroof the hydrocarbon content at the upper surface.

The nature of my invention will be more fully appreciated from the following description ofa specific embodiment thereof, which has been illustrated diagrammatically in the accompanying drawing.

In the drawing the numeral I designates a tower which is relatively tall compared with its crosssection and is insulated by heat insulation 2. This tower ispartly filled with pervious packing material 3 such as crushed fire-brick, ceramic rings,-or the like supported on a supporting grid 4, The essential purpose served by the packing is to inhibit vertical mixing and thus-prevent liquid near the buttOIIl, from which hydrocarbon has been removed, from returning to a higher point in the apparatus and thus diluting the hydrocarbon-rich plying steam. Preferably the steam is distributed,

by a. distributor 8 within the tower. An outlet 9 is provided near the top of the tower for withdrawal of vapor products. A thermostat I0 a. few feet below the foam -breaking level ll may be provided,

the top of the evaporator plates or flooded bubble trays C. is introduced into to control the flow of steam by means of a valve H! on steam line 1.

In the preferred operation of this system an aqueous detergent solution which may have the following composition by weight:

Surface-active organic sul fltation pmduct consisting essentially of-sulfonated ketones, sulfonated amines, sulfonated sulfamates, and water-soluble inorganic salts, such as can be obtained by the process of United States Patent 2,265,993 25 is introduced at an elevated temperature, preferably 60 to 70 0., through inlet 5. Steam (ordinary saturatedsteam under about 50 lb. gage pressure at 145-150 C.) is introduced at l and allowed to percolate up through the aqueous solution in the packing 3. The steam in passing up through the solution picks up vapors of the petroleum naphtha and isopropyl alcohol andcarrles them upwardly through the column in contact with aqueous detergent solution containing a grad ually increasing proportion of them. Vapors of the petroleum naphtha, isopropyl alcohol, and steam are withdrawn through detergent is withdrawn at 6. The flow of detergent in at 5 and out at 6 is regulated to provide the desired degree of removal of petroleum naphthe. and isopropyl alcohol, "and at'the same time to maintain the desired high concentration of petroleum naphthaat the available flow of detergent is inadequate to maincorresponding to at least 5% steam introduced at 1 maybe desired balance is obtained. v

In towers from 6 to 20 feet in height, the proccapable or reducing the hydrocarbon and alcohol content or an aqueous detergent of the type described'above to a small fraction of a. percent, for instance on the order-of" 0. and practically removal orthehydro? carbon has been effected.

The details of operation of my process naturally upon the composition'ofthe dethe liquid temperature at the-bottom of the: column is advantageously around 103. C. for thespecific detergent composition described.

For the treatment of detergent solutions initially containing less than 5% by weight of:hy-. drocarbon, the apparatus maybemodiiiedslizhtlv by shortening thepacked section for detergent solution and providing-amendeoutlet 9; aqueous foam-breaking level, designated H in the'drawing. If the maximum belowthe inlet tity of hydrocarbon of the type above may then'be added as a 90C. at this point by I steam flow.

solutions which tend 1 nated sulfamates, 15 to 25% hydrocarbon in said tional packed section abovethis inlet. A quanreferred to liquid at a point above the upper packed section to maintain the desired high concentration of the hydrocarbon at the top of the evaporating zone.

Detergent solutions having an inadequate concentration of hydrocarbon to assure satisfactory foam-breaking also may be treated in the type of apparatus illustrated in thedrawing merely by adding the requisite quantity of volatile liquid hydrocarbon, in the liquid form, to the solution or to the tower to provide a suitable high concentration at the foam-breaking level. This procedure has the disadvantage, as compared with the provision of a second section above the detergent inlet, of requiring. a somewhat larger quantity of hydrocarbon to maintain the same concentration thereof at the foam breaking level.

If desired, heat in addition to that supplied by the steam may be provided through the tower walls from an external source or by heating coils withinthe tower. By supplying additional heat, particularly in a region extending for a few feet below the foam-breaking level, the capacity of a tower of given cross-sectional area can be increased considerably.

In normal operation, as above described, the tower pressure is atmospheric at the top and only slightly greater at the base, the level of the liquid overflow [2 being near the base of the tower. If desired, a greater hydrostaticpressure at the base of the tower may be employed, forexample, by raising the level of the liquid overflow l2.

The separating process of the present invention may be controlled automatically in a very simple manner merely by providing a thermostatic control for the flow of 'steam while maintaining the detergent flow substantially constant. Thus, with the conditions of temperature prevailing in'the'case of the detergent previously considered, containing on the order of 8% of 'heptane, a thermostat may be provided. in the tower l at an intermediate point (for instance in a 12 foot column, at a point three or four feet below the foam-breaking level) to maintain a substantially constant temperature" of say' 85 to suitable control of the In a similar manner,other aqueous detergent v to foam and which contain hydrocarbons of the type above described may be treated; for example, the various'aqueous solutions obtained by the process of my ap plication Serial No. 427,321, filed January 19, l 1942; and especially those containing, per 100 parts by weight of solution, 6 to parts of hydrocarbon, 25 to 40 parts of solids, and the balcurrent flow in the column, a concentration of said hydrocarbon at least equal to said minimum foam-breaking concentration.

2. The method of removing a liquid hydrocarbon having a normal boiling point below 150 C., contained in an aqueous detergent solution tending to foam when the concentration of said liquid hydrocarbon in said solution is less than the minimum foam-breaking concentration of said hydrocarbon in said solution, which comprises passing said solution down through an evaporating column countercurrently 'to a flow of steam, including in the solution near the top of the countercurrent flow in the column a concentration of said hydrocarbon at least equal to said minimum foam-breaking concentration, and controlling the rate of flow of the steam so as to maintain, in the solution at the top of the countercurrent flow in the column, said hydrocarbon at least equal to foam-breaking concentration.

3. The method of removing a liquid hydrocarbon having a normal boiling point in the range to 150 C., contained in an aqueous detergent solution tending to foam, which comprises passing the solution down'through' an evaporating column containing the solution as the continuous phase, bubbling steam countercurrently up through the solution, and maintaining in the solution near the top of the column an amount of the liquid hydrocarbon equal to at least 5% by weight of the liquid phase. Y

4. The method of removing a volatile nonnormal boiling point in the range 50 C to 150 0., contained in an aqueous detergent solution tending to foam,

which comprises passing th solution down said minimum through an evaporating column containing the "ing level in the column ance water, the composition of the solids being:

40 to of a mixture of surface-active organic sulfitation products consisting essentially of sulfonated ketones, sulfonated amines and su1f0- of sodium sulfate, 10 to'14% of sodium chloride, 10 to 20% ofsodium sulfite, 6 to 10% of sodium bisulfite, 1 to 3% of sodiumsulfamate. Iclaim:

l l. The method of removing a liquid hydrocarbon having a normal boiling point below 150? C., contained in an aqueous detergent solution tending to foam when the concentration of said liquid solution is less than the minimum foam-breaking concentration of said hydrocarbon in said solution, which comprises passing said solution down through an evaporatdetergent solution as the continuous phase, bubbling steam countercurrently up through the solution, introducing near the top of the column hot, aqueous detergent solution containing the volatile non-aromatic hydrocarbon at a rate sufficient to maintain in the liquid at the foam-breaka concentration of said hydrocarbon atleast 5% by weight of the liquid phase, and withdrawing substantially hydrocarbon-free aqueous detergent solution from the base ofthe column. i

5. The method of removing a hydrocarbon having a normal boiling point in-the. range 50 to 150 C., contained in an aqueous solution of a surface-active organic sulfitation product consisting essentially of sulfonated ketones, sulfonated amines, sulfonated sulfamates, and watersoluble inorganic salts, said solution tending to foam when the concentration of said hydrocarbon in said solution is less than the minimum foam- -breaking concentration of said hydrocarbon in said solution, which comprises passing said aqueous solution containing said hydrocarbon down equal to said minimum foam-breaking concentration, and controlling the rate of'flow of the steam a concentration of so as to maintain infthe:solution at the ten of "the countercurrentrfiowlin:the:column, a, concentration of said hydrocarbon at leastr'equal xto saidxmihimum foam-breaking concentration,

' 6.,The 'methodof'removing a: volatile {non-Q aromatic". hydrocarbon having a normal boiling -point'inthe range-50: to 150 0.; contained in an --aqueous-solution of asurface-active organic sul- "fitation product 1': consisting essentially of sulfoo nated ketones;:sulfonated amines, sulfonated sulf amates, and water-soluble inorganicsaltsgsaid -solution tending'to-foamwhen the concentration of said hydrocarbon in said solutionis less than -ithe' minimum foam-breaking concentration'of said hydrocarbon :in said solution, which com-r prisesnpa'ssing sa-id aqueous solution containing ":said hydrocarbon down through anevaporating :column countercurrently toa flow of steam, :in- I icluding -in:thesluti0n' near the top ofthe countercurrentzflow in the column aconcentration bf:-

said hydrocarbon at least-equal to said minimum -=foam-.breaking concentration, and controlling the rate of flow of.- the steam'zso.as:tomaintain,.:in the solution-at the top of the countercurrent flow in the 1 column, a concentration of said hydrocarbon;

- at least equal to said minimum foam-breaking concentration.

7." The methodtofremoving a-petroleumnaphtha contained in an aqueous solutioniof-a surbreaking level in the column: an amountiofl the -,.'.petr0leum naphtha'equal-to atleast byweight of the solution. r I 8. The method-orremoving; a volatile nona-romatic hydrocarbon having 1; a normal boiling point in the range 50 to 150 C.,containedin an --aqueous solution of asurface-active organicsulfistation product consisting essentiallyof sulfonated ketones, sulfonated amines," sulfonated' sulfamates, :and water-soluble inorganic ysalts, which v.cornprises passing the solutioncontinuouslydown vtheylaqueous solution, introducing additional quantities of theaqueous solution containing; the

. hydrocarbon; at a; temperature of at least '60 --withdrawing substantially hydrocarbon-free solution substantially continuously :from .the base maintain in the-liquid atv the foam-breaking level in thezcolumna concentration for the hydrocarbon -.sat least-5% --by weight of: the liquid phase and. an

--efiluentdetergent solution at the base of. thE'COI-fi umn substantially" free. from hydrocarbon.

-9.- Theemethod of removing a-petroleum1naphatha contained, in .an aqueous solution of a 1 surrently up; through: the solution so as -to-evaporate .:the petroleum :naphthaf from :the: aqueous soluwtion, introducing 1 additional :quantities r of .the

, aqueous: solution: containin -the petroleum-naphtha at a-temperatureof atleast fi0f. C.', withdraw ing substantially naphthaefreersolution" substantially continuously from: the base, of the column, and1controllingthe introduction of steamiat'rthe base :of the column' so as to provide a-substantially constant temperature at an-intermediaterpointrof the columnpreselectfed to -maintain in .the liquid at the foam-breaking i level-in the :column 21; T6011- :centration of the :petroleumnaphtha at least -'5'% by weight of -.the liquid phaseandan -'efiluent-vdetergentsolutionat the base of the .column 'substantially free from: petroleum naphtha.

10. Themethod of removing a *liquidrhydrocarbon-having a'normal -boiling point below-150 C.,= contained :"in an aqueous .detergentrsolution tending to foam when the concentration nf "said hydrocarbon in said solution is less thana'the 'minimum foam-breaking concentration of said hydrocarbon vin saidv solution; which' comprises amassing!v the solution, 7 containingat least ':said

--;to maintain at least said'minimum foam-break- :minimumioam-breaking concentration of said hydrocarbon, down throughzan evaporating column countercurrently to a fiow 'of'a' hot rinert gaseous evaporating medium, andcoordinziting the-rate of floW'of-said evaporating medium with the'rate of downward flowiofsaid solution so as .ing concentration of the hydrocarbon in the :solutionnear-thetop of the column.

was

11. The method of removing aliquid hydrocarbon havinga normal --boiling: point below 150 0., contained. in: an aqueous r detergent: solution tending to foam when: the concentration-of said minimum.- -foam=breaking concentration of. said ..hydrocarbon .in said "solution, which comprises -=passing the -solution, -containing'r at deasta said 1 .minimum foam-breaking concentrationofr'said hydrocarbon, down through an evaporating: colcountercurrently :to-a flow" of steam; and coordinatingv the rate-of flow of the steam with the rate of downward flow ofsaid solution: sons-to maintain a substantially constant temperature at .apreselected intermediate: pointsin the column,

the temperature at said point beingrselectedeso .as .to, ,maintain at least said .minimumv foambreaking concentration of said hydrocarbonc' in the solution near the top .of'thecolumn.

l .12. The method of removing a liquid? hydrocarbon thaving -a. .boilingpoint 'below 0., contained in v an aqueous :detergent ---solution tending to: foam -when. thev= concentration of; said (hydrocarbon insaid solution is less than-rthe .minimum foam-breaking wconcentrationof said hydrocarbonin :said solution, which rcomprises -passing-the solution, containing at least' said minimum; foam-breaking concen'trationr ot .r-said hydrocarbon; down'through-an evaporating colminimum' foam-breaking concentration of :said

hydrocarbon in the solu-tionnear the "tOIIFOf't-thfi 'colunm.

- ALFRED FESSIL'rER. 

